Usage:
Maquoketa Shale (IL*,IN,IA*,KY,MN*,MO*,WI*, and KS*-subsurface)
Maquoketa Formation (IA,MN,MO)
Maquoketa Group (IL*,IN,MO*,WI)
Maquoketa Shale Group (IL)
[?] Maquoketa Supergroup (OH)
Subunits:
SUPERGROUP STATUS --in OH: unknown [not recorded in GNU records (USGS DDS-6)].
GROUP STATUS (alphabetical): Brainard Formation (IL,IN?), Cape La Croix Shale (MO), Dillsboro Formation (IN), Fort Atkinson Limestone (IL,IN) or Fort Atkinson Formation (IL), Girardeau Limestone (IL*,MO*), Kope Formation (IN), Neda Formation (IL), Orchard Creek Shale (IL*,MO*), Scales Shale (IL,IN) or Scales Formation (IL), Thebes Sandstone (IL*,MO*), Whitewater Formation (IN).
FORMATION STATUS (alphabetical): Brainard Member (IL*,IA*,WI*), Clermont Shale Member (IA) or Clermont Member (MN), Elgin Limestone Member (IA) or Elgin Member (MN), Fort Atkinson Limestone Member (IA,WI) or Fort Atkinson Dolomite Member (WI), Neda Member (IA*,WI*), Scales Member (WI), Wykoff Member (IA,MN).
Geologic age:
Ordovician, Late*
Cincinnatian*
Maysvillian*
Richmondian*
Type section, locality, area and/or origin of name:
Named from exposures on Little Maquoketa River, 12 mi west of Dubuque, Dubuque Co., eastern IA (US geologic names lexicons, USGS Bull. 896, 1200).
Reference section: in roadcut on U.S. Interstate Highway I-55, in SE/4 sec. 19, T. 42 N., R. 6 E., Herculaneum 7.5-min quadrangle, eastern Jefferson Co., eastern MO (Thompson, 1991).
AAPG geologic province:
Illinois basin*
Iowa shelf*
Ozark uplift*
Upper Mississippi embayment*
Wisconsin arch*
Forest City basin*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).